1. Field of Invention
This device is an improved recreational practice device which will rebound a playground size ball such as a soccer ball, kick ball, or a basketball which has been propelled against the device.
2. Discussion of Prior Art
There have been many ball rebound devices previously patented which attempt to rebound a ball to the user who tosses or kicks a ball to the device. These devices may be each grouped into one of the following four categories. Reference the applicable patents in each category:
1) Pre-Woven fabric or net stretched taut within a frame,
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2) Rigid rebound panel,
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3) Rigid rebound panel with springs, 4553751
4) Modified trampoline--stretched fabric or net within a spring assisted frame, 4119311 5007638
1) Pre-Woven fabric or net stretched taut within a frame: These devices rebound a ball which has been tossed, kicked or otherwise propelled to it by a simple pre-woven fabric or net which has been stretched across a frame. The rebound surface provided by this class of devices has a limited capacity for rebounding a ball with appreciable speed. This is believed to be due to the inherent design and construction of a net. For example, a net is primarily designed to "trap" or "stop" an object which strikes it. A net is a pre-woven assembly of stings which are sewn or connected with knots, usually in a zigzag pattern and usually has a perimeter routed cord or piece of fabric which is used to attach it to a frame. When impacted by the ball this zig-zag assembly of connected strings quickly dissipates the kinetic energy of the ball across the entire expanse of the net. This is why nets are excellent applications when used as backstops at baseball fields, batting cages, tennis courts, etc. No matter how taut a net is stretched, it still has a limited ability to efficiently rebound a ball due to its inherent design and construction. There are many types of materials and variations of nets. However, they all face the same severe limitation--they absorb and dissipate an appreciable amount of energy from the ball instead of efficiently storing and then re-administering the energy to the ball.
2) Rigid rebound panel: These devices each consist of large solid panels which serve as a backboard to rebound a ball which has been tossed or kicked to it. This is another simple approach to a ball rebound system. However, since the panels are solid and do not react at all in response to the ball, the rebound velocity depends largely upon the compression of the ball upon impact with the panel and the inherent tendency of the ball to quickly achieve the expanded condition. In other words, this class of devices takes an inactive role in the rebound of the ball upon impact.
3) Rigid rebound panel with springs: These devices are a modification of the rigid rebound panel in that springs have been attached to the rigid panel to provide some ability of the panel to absorb to energy from the ball upon impact of the ball and return energy to the ball as it is rebounded from the panel. This concept is a rudimentary improvement to the rigid panel ball rebound system, but the rebound velocity of the ball is still largely dependent upon compression of the ball and the inherent tendency of the ball to quickly return to its expanded condition. These devices may also contain other parts such as fasteners connecting the springs to the panel and a frame which inherently introduce undesirable friction into the ball rebound device.
4) Modified Trampoline: In this device, a pre-woven fabric is stretched taut within a frame by a series of springs around its perimeter. In this case, the fabric is usually inelastic, and depends primarily upon the springs to collect and re-administer the energy absorbed from the ball. Due to the fact that the fabric is relatively inelastic, and is largely an assembly of loosely woven strings, it tends to act in the same way as the net stretched taut within a frame. Much of the kinetic energy of the ball is quickly dissipated throughout the fabric as it is a pre-woven assembly of thread or string material--like the net, and therefore cannot re-administer the energy to the ball during the rebound. In some cases a net has been substituted for the fabric with springs attaching its perimeter to the frame.